Pressure safety device.



L. A. SHELDON.

PRESSURE SAFETY DEVICE.

APPLICATION FILED APR. 14. 1917.

1,250,680. Patented Dec. 18,1917.-

Figi Fig.2.

7 8 I I e Inventor": Luciano S el on Hisa ttor-ney.

LUCIAN A. SHELDON, or SCHENEGTADY, NEW YORK, ASSIGLN'OR 'ro GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

PRESSURE SAFETY DEVICE.

Specification of Letters Batent.

To all whom it may concern:

Be it known that I, LUCIAN A. SHELDON, a citizen of the United States, residing at Schenectady, county of Schenectady, in the State of New York, have invented certain new and useful Improvements in Pressure Safety Devices, of which the following is a specification.

In-the mercury turbine power system disclosed in the patent to Emmet No. 1,167,158, dated January 4, 1916, there is found a condenser into which the mercury vapor from the mercury turbine exhausts and in which are tubes which form a boiler for asecondary fluid, as water, and which at the same time serve as condenser tubes. The condenser contains a good vacuum while the boiler tubes carry a high pressure.

The primary object of my invention is to provide an improved safety device for use wherever conditions as above described are met with which will protect the condenser casing or other apparatus against the pressure to which it would be subjected should one of the above referred to boiler tubes blow out.

A further object of my invention is to provide'a safety device for use under the conditions specified which will be very sim ple and cheap to construct and absolutely sure to perform its function when called upon.

FOr a consideration. of what I believe to be novel and my invention, attention is directed to the accompanying specification and the claims appended thereto.

In the accompanying drawings, Figure 1 'is a diagrammatic view partly in section of a portion of a power system as above described with my invention applied thereto; Fig. 2 is a section illustrating the construction of the safety device, and Fig. 3 is a sec-v tion taken on line 33, Fig. 2, and partly broken away to show certain of the parts.

Referring to the drawing, 5 indicates a portion of a furnace having a stack 6. 7 is a condenser casing covered with heat insulating material 8, and 9 are boiler condenser tubes therein. 10 indicates a turbine wheel which. is located in the condenser casing 7, and which in this case utilizes mercury vapor which enters through conduit 11. It will be understood that suitable means are provided for maintaining a vacuum in the condenser casing 7.

As will be clear, Ordinarily the condenser casing is subjected on the Outside to atmos- Patented Dec.18, rear.

pheric pressure which, with a high vacuum within the casing 7, means a difference in pressure on the two sides of the casing of about 15 pounds per square inch. It is desirable in order to safely protect the apparatus that incase the pressure within the condenser should exceed that without by a small amount, for example about 7 pounds per square inch, that the safety device should operate. An ordinary frangible diaphragm arranged Over an opening. is the most satisfactory form of blow-out safety device as it is very simple in structure and sure in its operation, but Obviously it could not be used in the present instance as the pressure to which it would ordinarily be subjected on the outside is greater than that at which it is desired that it should blow out. According to my invention I provide a novel arrangement of frangible diaphragm which, while it will withstand the greater pressure to which it is normally subjected in the one direction, will blow out when subjected to a lesser pressure in the opposite direction. To this end I provide in the wall of the condenser casing 7 an opening 12 surrounding which is an annular reinforcing ring 13 fastened by rivets 1 1. Covering the opening 12 is a disk 15 which is fastened to the ring 1 3 by bolts 16, a. rabbeted joint 17 being provided to insure a tight connection.

In the disk 15 are a number of holes 18 and fastened over the holes 18 is a thin frangible diaphragm 19, the same being preferably welded to the disk 15 at its periphery, as indicated at 20. This gives an absolutely tight joint. The diaphragm 19, as already stated, is made very thin and in addition to this, it may be suitably scored, as indicated at 21, to render it as weak as required to have it give way when subjected. to the pressure at which it is intended to give way. These scores also define the lines along which the diaphragm will break and insure that the diaphragm will open up quickly to a large area thus insuring quick relief. The diaphragm 19 is locate on the side of the disk 15 which is subjected to the normal higher pressure, in the present instance this being the Outside. This normal higher pressure, while it is much greater than that which would ordinarily disrupt the dia-v phragm presses it against the disk 15 which forms a backing for it and serves in substance to divide the diaphragm up into a number of smaller diaphragms. The pres sure at which a frangible diaphragm will give way varies inversely with the diameter and when the diaphragm is divided up into a number of smaller diaphragms, as just described, each is then able to withstand the higher pressure, although the diaphragm as a whole would not. Owing to this arrange ment, therefore, in the system shown the diaphragm will not give way under the pressure to which it is ordinarily subjected on the outside. On the other hand, in case of an increase in pressure within the casing to a pressure somewhat above atmospheric, the frangible diaphragm since it is now subjected over its entire area to this pressure will at once give way.

In the arrangement shown the opening 12 is connected by a pipe 21 to the stack 6, the pipe being carried by a ring 22 fastened to disk 15 by bolts 16. In case the diaphragm 19 blows out, the contents of the condenser are vented to the stack 6.

By the structure described, it will be seen I that I provide a frangible diaphragm which will withstand a very much higher pressure on the one side than on the other, and hence is peculiarly adapted for use under conditions as met with, for example, in the apparatus described. It will be understood, however, that the invention is not limited to this use, but may be used wherever similar conditions obtain. It will also be understood that the numerical pressures referred to above are only by way of example, and that any pressure congitions met with could be readily provided or. I

In accordance with the provisions of the patent statutes I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof; but I desire to have it understood that the apparatus shown is only illustrative, and that the invention can be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. The combination with a casing wall having an opening, of a blow-out safety deme eeo vice therefor comprising a plate having a plurality of openings therein and a frangible diaphragm covering said openings, said plate being fastened over the opening in the casing wall.

2. In a pressure safety device, the combination, of a casing having a plurality of openings through a wall thereof, and a frangible diaphragm covering all said openm s. 1

The combination with a casing wall,of a frangible safety device therefor which will withstand a certain pressure in one direction having a plurality of adjacent openings therein, of a blow-out safety device therefor comprising a frangible diaphragm located over said openings, the material between said openings serving as a means for backing up the diaphragm on one side but permitting all such side to be exposed to pressure.

5. The combination with a casing having a plurality of adjacent openings in its Wall and having a pressure on its outside greater than that on the inside, of elements within the casing which normally carry a pressure greater than the outside pressure, and means for protecting the casing in case one of said elements should break and subject the interior of the casing to a pressure but slightly (in excess of the pressure on the outside of the casing, said means comprising a thin frangible diaphragm located on the outside of said casing and covering said openings whereby as to the pressure on the outside of the casing it acts as a plurality of smaller diaphragms, and as to the pressure on the inside of the casing it acts as a single larger diaphragm.

In witness whereof, I have hereunto set my hand this 12th day of April, 1917.

LUCIAN A. SHELDON. 

